1. Field of the Invention
This invention pertains to a multiple gravel pack screen assembly adapted to produce fluids from a well in an earth formation from separate and isolated gravel packed zones wherein a permeability reducing fluid is injected into an intermediate layer of gravel between the zones from a sub interposed in the gravel pack assembly.
2. Background
U.S. patent application Ser. No. 08/137,870, filed Oct. 15, 1993 by H. Mitchell Cornette, et al and assigned to the assignee of the present invention, describes one method of providing a multiple gravel pack type well completion for producing fluids from two spaced apart zones in an earth formation. U.S. Pat. No. 5,145,004 to H. Mitchell Cornette, also assigned to the assignee of the present invention, describes an arrangement for producing fluids from multiple zones utilizing gravel packed wells with an auger gravel pack screen assembly.
In certain wells which are capable of producing fluids from multiple spaced apart zones, intermediate layers of formation material may produce water and/or gas which is unwanted when producing crude oil, for example, from the formation zones on each side of the water or gas producing zone. Moreover, one or the other of the two spaced apart production zones may begin to produce unwanted quantities of water and/or gas. The flow of water and/or gas into an oil production well or water into a gas production well creates several problems such as, in the case of water incursion, requiring artificial lift, development of corrosion of the well structure due to mixing of oil with acidic gases and reduction in the production rate of the desired fluids.
Although patent application Ser. No. 08/137,870 describes one solution to the abovementioned problem which is useful with auger type gravel pack screen assemblies, there are instances when this type of screen assembly can not be used, such as in relatively high angle or substantially horizontal wellbores. In this regard more conventional gravel pack screen assemblies are sometimes required. However, the aforementioned problems associated with isolating spaced apart zones or shutting off production from one zone while producing from an adjacent or closely spaced zone still exist for conventional as well as auger type gravel screen assemblies. Accordingly, the present invention provides a unique solution for multiple gravel pack screen assemblies wherein a permeability reducing material may be injected into a portion of the gravel packing interposed between two spaced apart gravel pack screens, which may be the so called auger type or other types.
Those skilled in the art will recognize this improvement upon reading the summary and detailed description of the present invention which follows herein.